Liquid washing effect observed in isothermal pilot unit



Aug. 11, A1959 D. F. HILL METHOD FOR INCREASING CATALYST ON-STREAM TIME IN A HYDROGENATION PROCESS 2 sheets-sheet 1 File-1 neo. 7, 195e` O kD vON

1M Nouvzlen -mms3@v INVENTOR. Dona/d F H' I Agen# Aug. 11, 1959 D. F. HILL 2,899,383

l METHOD vFQR INCREASING CATALYST ON-STREAM TIME IN A HYDROGENATION PROCESS Filed Dec. '7, 1956 2 Sheets-Sheet 2 @mms mi; s mm zo 2,399,383 Patented Aug. 11, 1959 METHOD FOR .INCREASING .CATALYST -ON- STREAM TIME `1N A HYDRGGENATION PROCESS Donald F. Hill, West Deptford Township, Gloucester kCour1ty,-N..`I., :assignor to Socony Mobil .(lilCompany,

Inc., a corporation of New York Application December 7, 1956, Serial No. 626,958 Y 3 Claims. (Cl. 208-143) dproduct color.

"hourly space velocity (3 volumes liquid feed per hour per Avolume of catalyst) with a circulation of 1500 s.c.f. (standard cubic feet) of hydrogen per barrel of 4feed at 610" F. and 500 p.s.i.g. gave-a 91-92 percent desulfurization of a catalytically cracked feed and a-product color of D-l. Somewhat heavier stocks were treated under the -more severe conditions indicated Vin Figure 1 for a period of about 1l days lat which time 1the `activity of the catalyst had decreased `to an extent that under the check run Aconditions (3 LHSV, 1500 s.c.f. Hz/b., 610 F., 500 p.s.i.g.) the catalytically cracked feed was only de- `sulfurized `about 60 percent lduring the eleventh day. Reaction conditions from about 11 to 13 days were such that between 50 percent and 65 percent of the charge stock was in the liquid phase ,duringhydrogenation The activity of the catalyst was restored as indicated by increased desulfurization yof the :charge stock and vimproved The data presented in Figure l are summarized in Table I.

TABLE 'I Catalyst Activity ,Actual treating conditions Based on Check Run Conditions 1 Time, :Days

Charge, LHSV, Hz/Oil, Temp., Pressure, Percent Product Percent BR, F. v.-/hr./.v.. s;c.f./b. 'F. p.s;i.g. inVapor Color Desnlfur- Phase t ization 350-650 Varied Varied Varied 500 Varied 380-590 3 1, 500 61 500 35 40G-750 1-2 2,' 150 1 `750-775 5,00 70-90 S50-700 1-.2. 1, 900 750-.775 500 .100 ,550-950 1-2 2,v 250 750-7 75 500 15-20 3BG-590 3 1,400 610 500 35 S80-590 3 1, 400 .610 500 35 380-590 4 1, 400 650 '500 50 1 BSO-590 i4 1, 400 G50 500 50 1 Treating a S80-1590 F. charge at 3 LHSV, 1,500 s.c.f. He/b., 610 F., and 500 p.s.i.g.

With the increase in the .use of oil for domestic heating it has become necessary to include in the domestic heating oil greater and greater amounts of cracked oil of the domestic heating grade. This increased proportion of catalytically cracked stock has increased the amount of sediment deposited on home burner pump strainers. Several methods of treating .have been suggested but the best by far is hydrogenation of the catalytically cracked lightdistillate or the mixture of cracked light distillate and straight run .distillate `fuel oil.

Since the light `distillate fuel oil is a relatively Acheap product of the refinery it is highly desirable to treat ,the material as kcheaply as possible. One means of obtaining more efficient hydrogenation is to operate at pressures and temperatures under which a major portion, say '70 percent, of the light distillate is in the vapor phase. However, as the proportion of the feed to the hydrogeneration reaction which vis in the vapor phase increases the amount of carbonaceous .material or coke deposited on .the hydrogenationcatalyst increases. That is ,to say, when less than 20 percent of the petroleum fraction to be treated is in the liquid phase under reaction conditions of temperature, pressure and hydrogen to oil ratio the deposition Aof carbonaceous material upon the catalyst increases to such an extent kas to markedly affect the on-stream time, i.e., .the time between regenerations of the catalyst. An appreciable portion ofthis deposit n can be removed and the on-streamtime considerably increased in a simple manner not involving combustion of the catalyst contaminating carbonaceous deposit. This is illustratedby the data presented in Figures 1 and'Z.

Heating oil fractions of petroleum oil having boiling ranges in the range of 3--50j650 F. :had vbeen `hydro- These data emphasize the principles of the present invention in that, after contact of the catalyst with feed -under conditions such that only 35 to v50 percent of the feed was in the vapor phase, i.e., 50 to 65 percent of the -feed was in the liquid phase, 4the activity ofthe catalyst and `the color of the product were restored. In other words, duringthe 149 to '156.5 (0 to 7.5 days in Figure 1) days ofen-stream ,time thereaction conditions were such that about 70 to about 100 percent ofthe feed was in the vapor phase and the catalyst activity decreased.

`(Possibly due, in part at least, to low H2 flow in the 154 to 154.8 day period.) Thereafter during the next about .3.4 days reaction conditions were such Vthat to 85 lpercent ofthe 'feed was in the liquid phase as compared to zero to 30 percent in the liquid phase during the previous 7.5 days. Activity checks could not be made in :this-period. The activity of `thecatalyst and the .color .-of lth'eproduct `were steadily improved in the 159:8 to

'161.8 day `period with only `50 .to 65 percentof the feed .2in the liquid phase.

`In vanother protracted `on-strearn period ya .petroleum fraction (heating oil fraction) yhaving a boiling Vrange of -420-700" F. was contacted with a cobalt molybdate catalyst l0 LHSV and 700 iF. .at .250.p.s.i.g. kwithacirculation of 1000 s.c.f. of hydrogen per barrel of feed treated. Under -these conditions about to 100 -per- -centof ythe feedwas in the vapor phase kinthe Areaction zone. Catalyst-activity check-runs at 650 -Fuwere made lto determine catalyst activity at vthe beginning lof the `on-stream period and at 'the end of I6.6 weeks. The degreeof .desulfurization showed .thatinitially the feed was desulfurized tothe extent of about'84 percent whereas at Vthe end of 'the 6.6 week period 'the 'feed was' only 3 about 76 percent desulfurized. Thereafter, for about 4 days a similar 400-650 F. feed was treated under reaction conditions such that only about 50 to 60 percent of the feed was vaporized, 40 to' 50 percent as contrasted with zero to percent was in the liquid phase. During this reconditioning period, the activity of the catalyst as measured by the degree of desulfurization of the feed was restored. Subsequently, the reaction conditions were restored to the original combination of conditions and the charge stock as in the above-mentioned check runs was treated with 84 percent desulfurization of the feed. These data are graphically presented in Figure 2 and summarized in Table II.

4 Thereafter, the same charge stock was hydrogenated under the following conditions:

Run No. CDS 235A 235C Temperature, F 643 643 Pressure, p.s.i.g 500 600 LHSV, v./v./hr 2. 5 2. 5 H2:Oil s.c. 1,350-1,700 1,575 Av'g.) Product Color, N PA D5 L5 Thus, `during runs 232A, 233A and 234A about 75-100 percent of the feed stock was in the vapor phase and Those skilled in the art will recognize that increasing the reaction pressure after 6.6 weeks ori-stream fromV 250 p.s.i.g. to 500 p.s.i.g. whereby the portion of the feed in the liquid phase was increased to 40 to 50 percent restored the activity of the catalyst to the original..

level.

temperature and hydrogen-to-oil ratio existing in the reaction zone have to 100 percent in the vapor phase and 80 to zero percent in the liquid phase until a ca rbonaceous deposit forms on the catalyst and then periodically hydrogenating stock under conditions of temperature, pressure and hydrogen-to-oil ratio such that the liquid volume passing over the catalyst is increased by at least percent with a minimum liquid volume'equal to 20 percent of the charge stock,

The amount of charge stock in the liquid phase in the hydrogenation reactor can be increased by lowering the temperature or increasing the pressure or concomitantly lowering the temperature and increasing the pressure.

One means of determining that the carbonaceous deposit is being removed from the catalyst under these conditions is the color of the liquid effluent from the hydrogenation reactor. Thus, for example, after hydrogenating a catalytically cracked distillate fuel oil having the following characteristics F. 10 percent point 470 90 percent point 560 End boiling point 610 Run N0. CDS 231A 232A 233A. 234A.

650 701 746 794 500 500 500 500 2. 5 2. 5 2. 5 2. 5 1,350-1,700 1,575 AVg.) Product Color L 1% L 1% L 1%] L 1% Accordingly, the present invention provides for hydro-Vv Ygenating stocks which under the conditions of pressure,

,pared to the color of the product (L11/2, run 231A),

only about 0-25 percent of the feed stock was in the liquid phase.

Furthermore, it Will be noted that the color of the product (D5, run 235A), during the period when 50-55 percent of the charge was in the liquid phase as comduring the period when 50-55 percent of the charge stock was also in the vapor phase is indicative that the catalyst was being freed of the carbonaceous deposit.

prises subjecting in the presence of hydrogen and a par- Accordingly, the catalyst activity which had been de- "creased by the hightemperature runs was improved during the Washing.

The present invention provides for subjecting a fhydrocarbon charge stock such as a light distillate fuel oil, a heavy distillate fuel oil, a short resid, a long resid, or

in general a mixture ofhydrocarbons (which under conversion temperature and pressure has about 0-80 percent of said mixture in the liquid phase) to conversion conditions as indicated by the equilibrium ash evaporation temperature until the carbonaceous deposit laid .Y down upon the catalyst is excessive as indicated by a p, darker colored product and/or a decrease in catalyst activity, changing at least one of reaction temperature and reaction pressure to provide reaction conditions under which the liquid phase is increased by at least 25 percent with a minimum of 20 percent of the charge stock in the liquid phase, continuing to convert said charge stock under the latter conditions of reaction temperature and pressure until the color of the product is restored `to the first color, and then resubjecting the charge stock to reaction conditions of temperature and pressure under which 0-80 percent of the charge stock is again in the liquid phase.

I claim:

l. A method of converting hydrocarbons which comticle-form solid catalyst a charge mixture comprising a hydrocarbon mixture having an initial boiling point not less than about 350 F. and substantially devoid of added diluent hydrocarbons to first reaction conditions of temperature and pressure under which about zero to 80 percent of said charge mixture is in the liquid phase to i first reaction conditions in the presence of hydrogen and in the substantial absence of added diluent hydrocarbons until said deposit of carbonaceous material on the catalyst becomes excessive, changing at least one of said first .ICaCtOn Conditions to provide second reaction conditions of temperature and pressure under which the proportion of the aforesaid charge mixture which is in the liquid phase is increased by at least 25 percent and having at least 20 percent of the aforesaid charge mixture in the liquid phase, subjecting the aforesaid charge mixture to said second reaction conditions in `the presence of hydrogen and a particle-form solid catalyst until said excessive deposit of carbonaceous material on the catalyst is substantially reduced by the liquid phase material thus derived solely and created in situ from the charge mixture, changing at least one of said second reaction conditions to provide reaction conditions under which at least 20-100 percent of the aforesaid charge mixture is in the vapor phase and the balance if any is in the liquid phase, and subjecting the aforesaid charge mixture to the last-mentioned reaction conditions of temperature and pressure in the presence of hydrogen and a particleform solid catalyst, whereby the hydrocarbon conversion is carried out with the same hydrocarbon charge mixture throughout the entire operation.

2. The method of claim 1 wherein at least 800 cubic feet of hydrogen per barrel of hydrocarbon charge mixture is introduced into the reaction zone.

3. A method of hydrogenating a charge mixture of hydrocarbons having a percent point of about 380 to about 470 F., a 90 percent point of about 480 to about 625 F., and an end boiling point of about 530 to about 660 F., which comprises subjecting the aforesaid hydrocarbon mixture substantially devoid of added diluent hydrocarbons to a reaction temperature of at least about 750 F. and a reaction pressure of at least about 500 p.s.i.g. in the presence of a particle-form catalytic material and at least about 800 cubic feet of hydrogen per barrel of hydrocarbon mixture whilst about 0 to about 35 percent of the aforesaid hydrocarbon mixture is in the liquid phase until the color of the product produced becomes darker than that of the product as originally produced, and/or catalyst activity decreases, reducing the reaction temperature below 750 F. to provide reaction conditions under which the volume of the aforesaid hydrocarbon mixture which is in the liquid phase is increased to at least 20-100 percent of said hydrocarbon mixture and the balance if any is -in the vapor phase, subjecting the aforesaid hydrocarbon mixture to a temperature below 750 F. in the presence of hydrogen while about 20-100 percent of the hydrocarbon mixture is in the liquid phase until the product color and/ or catalyst activity is substantially improved by contact of the catalyst with the liquid phase material thus derived solely and created in situ from the charge mixture, changing said reaction temperature to a reaction temperature of at least about 750 F. to provide reaction conditions under which the volume of the aforesaid hydrocarbon mixture which is in the liquid phase is decreased so that only about 0-35 percent of said hydrocarbon mixture is in the liquid phase, and in the presence of hydrogen but in the substantial absence of added diluent hydrocarbons subjecting the aforesaid hydrocarbon mixture having only about 0-35 percent in the liquid phase to a reaction temperature of at least 750 F. and a reaction pressure of about 500 p.s..g., whereby the hydrocarbon conversion is carried out with the same hydrocarbon charge mixture throughout the entire operation.

References Cited in the le of this patent UNITED STATES PATENTS 

3. A METHOD OF HYDROGENATING A CHARGE MIXTURE OF HYDROCARBONS HAVING A 10 PERCENT POINT OF ABOUT 380* TO ABOUT 470*F., A 90 PERCENT POINT OF ABOUT 580* TO ABOUT 625*F., AND AN END BOILING POINTOF ABOUT 530* TO ABOUT 660*F., WHICH COMPRISES SUBJECTING THE AFORESAID HYDROCARBON MIXTURE SUBSTANTIALLY DEVOID OF ADDED DILUENT HYDROCARBONS TO REACTION TEMPERATURE OF AT LEAST ABOUT 750*F. AND A REACTION PRESSURE OF AT LEAST ABOUT 500 P.S.I.G. IN THE PRESENCE OF A PARTICLE-FORM CATALYTIC MATERIAL AND AT LEAST ABOUT 800 CUBIC FEET OF HYDROGEN PER BARREL OF HYDROCARBON MIXTURE WHILST ABOUT 0 TO ABOUT 35 PERCENT OF THE AFORESAID HYDROCARBON MIXTURE IS IN THE LIQUID PHASE UNTIL THE COLOR OF THE PRODUCT PRODUCED BECOMES DARKER THAN THAT OF THE PRODUCT AS ORIGINALLY PRODUCED, AND/OR CATALYST ACTIVITY DECREASES, REDUCTION THE REACTION TEMPERATURE BELOW 750*F. TO PROVIDE REACTION CONDITIONS UNDER WHICH THE VOLUME OF THE AFORESAID HYDROCARBON MIXTURE WHICH IS IN THE LIQUID PHASE IS INCREASED TO AT LEAST 20- 100 PERCENT OF SAID HYDROCARBON MIXTURE AND THE BALANCE IF ANY IS IN A VAPOR PHASE, SUBJECTING THE AFORESAID HYDROCARBON MIXTURE TO A TEMPERATURE BELOW 750*F. IN THE PRESENCE OF HYDROGEN WHILE ABOUT 20-100 PERCENT OF THE HYDROCARBON MIXTURE IS IN THE LIQUID PHASE UNTIL THE PRODUCT COLOR AND/OR CATALYST ACITVITY IS SUBSTANTIALLY IMPROVED BY CONTACT OF THE CATALYST WITH THE LIQUID PHASE MATERIAL THUS DERIVED SOLELY AND CREATED IN SITU FROM THE CHANGE MIXTURE, CHANGING SAID REACTION TEMPERATURE TO A REACTION TEMPERATURE OF AT LEAST ABOUT 750*F. TO PROVIDE REACTION CONDITIONS UNDER WHICH THE VOLUME OF THE AFORESAID HYDROCARBON MIXTURE WHICH IS IN THE LIQUID PHASE IS DECREASED SO THAT ONLY ABOUT 0-35 PERCENT OF SAID HYDROCARBON MIXTURE IS IN THE LIQUID PHASE, AND IN THE PRESENCE OF HYDROGEN BUT IN THE SUBSTANTIAL ABSENCE OF ADDED DILUENT HYDROCARBONS SUBJECTING THE AFORESAID HYDROCARBON MIXTURE HAVING ONLY ABOUT 0-35 PERCENT IN THE LIQUID PHASE TO A REACTION TEMPERATURE OF AT LEAST 750*F. AND A REACTION PRESSURE OF ABOUT 500 P.S.I.G., WHEREBY THE HYDROCARBON CONVERSION IS CARRIED OUT WITH THE SAME HYDROCARBON CHARGE MIXTURE THROUGHOUT THE ENTIRE OPERATION. 